Contact-positioning structure for a resilient connector insulator



May 18, 1965 R. H. ELLIS 3,184,701

CONTACT-POSITIONING STRUCTURE FOR'A RESILIEN'I CONNECTOR INSULATOR FiledSept. 25, 1961 3 Sheets-Sheet 1 INVENTOR.

B0651? E E2415 M fd/me/ R. H. ELLIS May 18, 1965 CONTACT-POSITIONINGSTRUCTURE FOR A RESILIENT CONNECTOR INSULATOR 3 Sheets-Sheet 2 FiledSept. 25, 1961 INVENTOR. H0 65E 1% 2445 May 18, 1965 R. H. ELLIS3,184,701

CONTACT-POSITIONING STRUCTURE FOR A RESILIENT CONNECTOR INSULATOR FiledSept. 25. 1961 3 Sheets-Sheet 3 R m m V W m vQ QQ a N 6 R QN k 8% 5 W\QIEI 147702NEyS,

United States Patent 3,184,701 CONTACT-POSITIONING STRUCTURE FOR ARESILIENT CONNECTOR INSULATOR Roger H. Ellis, Arcadia, Califi, assignor,by mesne assignments, to International Telephone and TelegraphCorporation, New York, N.Y., a corporation of Maryland Filed Sept. 25,1961, Ser. No. 140,580 7 Claims. (Cl. 33959) The present inventionrelates to electrical connectors wherein a plurality of contactterminals are mounted in one insulation body or block and complementarycontact terminals are mounted in another insulation body or block.Normally one set of the contact terminals would be pins and thecomplementary set would be sockets, but other types of mating terminalscan be employed. The present invention relates particularly to .themounting and positioning of the contact terminals in an insulation bodywhich is composed of resilient elastomer material.

Electrical connector insulation bodies for supporting a plurality ofcontact terminals are in many instances composed of resilient elastomermaterial. Among other advantages, such resilient insulator bodies can bemade in one piece while still having undercut cavities in the contactterminal-receiving bores of the insulator, whereas with rigid insulationbodies two or more blocks of insulation material are required to providesuch undercut cavities for positioning and retaining the contacts in thebores. This unitary resilient insulator structure simplifies connectorconstruction and eliminates moisture traps usually present in multiplerigid insulator structures, and resiliency tive bores in the insulationbody from the rear end thereof so that the contacting ends of theterminals either protrude or are accessible from the forward end of theinsulation body in position for effecting physical and electricalengagement with mating terminals. The insulator bores and terminals insuch connectors have complementary shoulders so that when the terminalsare fully advanced they will become locked in place against axialmovement in either direction. By this means, the connectors comprisinginsulation bodies and outer shells may be completely made up with theexception of the contact terminals, and the terminals may then beindividually connected at their rear ends as by crimping, soldering,welding or otherwise to respective conductor wires, and then theterminals inserted into the insulator bores from the rear.

Furthermore, by the application of a sufiicient rearward force, theresilient insulation material defining the shoulders in the bores willgive way to permit rearward removal of the termianls for replacement orrepair or reconstituting the pattern in a multiplicity of terminals.

Despite the above and other advantages in the use of resilient connectorinsulation bodies, one difficulty which has been found to be present inconnection with resilient "ice insulation bodies, particularly wheresmall size contacts are employed, is that when a contact terminal ispushed into its respective bore in the insulation body it is usuallydifficult to determine when the terminal has reached its correctforwardmost limit of travel due to the fact that the arresting shoulderin the bore is composed of the resilient insulation material, and willgive way somewhat when it engages a complementary shoulder on thecontact. This problem can be minimized when the terminals are insertedin factory production by the use of proper equipment which limits theextent of insertion of the contacts, but in the usual circumstancewherein the terminals are attached to conductors and inserted in thefield, the problem is serious.

A further problem in connection with the use of such resilient insulatorbodies in electrical connectors is that the shoulders in the bores ofthe insulation body which retain the terminals against axial movement ineither direction once the terminals are properly inserted in the boresare also of the resilient insulation body material, and therefore permita certain amount of axial shifting of the terminals and uncertainty inthe positiveness of the mounting of the terminals.

In view of these and other problems it is an object of the presentinvention to provide a resilient electrical connector insulation bodywith a contact terminal-receiving bore having a substantially rigid stopshoulder member secured therein for positively limiting the finalpositioning of a contact terminal which is inserted into the bore.

Another object of the invention is to provide, in a resilient electricalconnector insulation body having a pinrality of contactterminal-receiving bores therethrough, a web or matrix of substantiallyrigid insulation material which is molded into the resilient insulationbody and which presents rigid stop shoulder means in each of theterminal-receiving bores for limiting axial movement of the contactterminals in at least one direction in the bores, and it is also anobject of the invention to provide a novel method for producing theresilient insulation body with this contact positioning web or matrixdisposed therein.

Further objects and advantages of this invention will appear during thecourse of the following part of this specification, wherein th detailsof construction, mode of operation and novel method steps of preferredembodiments of the invention are described with reference to theaccompanying drawings, in which:

FIG. 1 is a vertical section, with portions in elevation, illustratingthe molding of a resilient electrical connector insulation body with thecontact positioning web of the present invention disposed therein.

FIG. 2 is a perspective view showing the cont-act positioning web ormatrix which is being molded into the insulation body in FIG. 1, the webor matrix as shown in FIG. 2 being attached to supporting structure forconvenience in coating the web or matrix so that it will be intimatelybonded within the resilient insulation body.

FIG. 3 is a perspective view of the Web or matrix shown in FIG. 2 afterit has been broken away from the supporting structure.

FIG. 4 is a plan view illustrating a web or matrix similar to that shownin FIGS. 2 and 3 but embodying a large number of individual contactterminal positioning rings.

FIG. is an enlarged, fragmentary vertical section illustrating a portionof the mold of FIG. 1 prior to closing of the mold, and particularlyshowing the split core pin arrangement employed in the mold and themanner in which the contact positioning web is placed in the mold beforethe mold is closed.

FIG. 6 is a view similar to FIG. 5, but with the mold in the closedposition and the resilient insulator body formed within the mold.

FIG. 7 is a greatly enlarged fragmentary vertical section showing aportion of the contact positioning web.

FIG. 8 is an enlarged, fragmentary vertical section illustrating themounting of a pin contact terminal in a bore of the resilient insulationbody, and particularly showing the manner in which an individual ringportion of the positioning web limits forward positioning of the contactterminal.

FIG. 9 is a view similar to FIG. 8, but illustrating the mounting of asocket contact terminal.

FIG. 10 is a fragmentary vertical section showing a modified form of thesubstantially rigid contact positioner.

FIG. 11 is a cross-sectional View along the line 1l-11 of FIG. 10.

FIG. 12 is a fragmentary sectional view similar to FIG. 10, butillustrating an additional modification in the structure of FIG. 10.

FIGS. 1, 5 and 6 illustrate one form of apparatus in which a resilientelastomer insulation body for an electrical connector may be molded.These figures, as well as FIG. 8, illustrate a resilient insulation body10 which is adapted to receive and support therein a multiplicity of pincontact terminals. A similar insulation body for receiving andsupporting socket contact terminals is shown in FIG. 9, and will bedescribed in detail hereinafter. It will be understood that both theexternal shape of insulation body 10 and the wall configuration of theterminal-receiving bores extending through insulation body 10, will varyaccording to the type and shape of connector in which the insulationbody is employed, and the type and configuration of the contactterminals which are mounted in' the insulation bodya Further, althoughthe insulation bodies shown and described herein are particularlyadapted for receiving pin and socket contact terminals, itwill beappreciated that they may be adapted to receive other mating types ofterminals, such as hermaphrodite terminals, within the scope of theinvention.

The insulation body 10 may be molded from any desired resilientdielectric material; i.e., the material may be any desired elastomerinsulation material. Examples of some suitable elastomer materials whichmay be used, but to which the present invention is not necessarilylimited, are neoprene (polychloroprene), natural rubber, silicone,polyurethane, buna-S (butadiene-styrene type), buna-N (buna nitrite), orthe like.

The resilient insulation body 10 may have a substantially' uniformhardness throughout, or it may may have portions of different hardnessesas set forth in US. patent application Serial No. 95,770, filed February27, 1961, for Multi-Hardness Resilient Connector Insulator. Although thepresent invention is not limited to the use of a resilient insulationmaterial for the, insulation body of any particular hardness, it hasbeen found in practice that a preferred maximum hardness is about 85(Shore Durometer), the hardness of the resilient insulation materialbeing controlled by the amount and type of filler mate-rials which aremixed in with the elastomer material.

The following is a formula which has been found ac ceptable for themolding of the resilient insulation body, and is set forth by way ofexample only, and not by way of limitation.

Table I below lists the ingredients and quantities thereof by weightwhich are combined to form a batch of the material for moldinginsulation body 10. It will be appreciated that the size of this batchis merely a convenient one, and may be varied as desired, provided therelative weights of the ingredients in the batch are as indicated.

Table I Ingredient: Weight in pounds Neoprene WRT 85.00

Stearic acid (rubber grade, such as S-tearite) 1.00 Magnesium oxide(such as Maglite M) 4.00 Zinc oxide (lead free, as by the FrenchProcess) 5.00 Siliceous material (such as HiSil 233) 25.00 Hard clay(such as Suprex clay) 30.00 Paraffine wax 1.00 Polyethylene (such asPlaskon 8406). v 2.00 Anti-oxidant (such as Aminox) 2.00 Ultra-marineblue (such as 1285 Blue) 0.50 Titanium dioxide (such as Unitane O220)5.00 Curing agent (such as NA-ZZ) 1.00 Neoprene GN comprising anel'astomer mas- Butaprene SL ter bat-ch. 15.00

Black color master batch 1.00

The black color master batch in Table I comprises the followingingredients in the following relative proportions'by weight: NeopreneGN, 100.00; coloring black (such as Wyex EPC Black), 50.00; sodiumacetate, 1.00; and light oil (such as Bear Flex LPO), 5.00.

The Neoprene WRT, Neoprene GN and Butaprene SL provide the base polymer,.while the stearic acid, magnesium oxide and Zinc oxide are standardingredients employed to modify the base polymer to provide desiredphysical characteristics in the final product. The siliceous material,HiSil 233, hardens and strengthens the final product, and the clay alsoacts to harden the product,

so that the siliceous material and clay may together he considered asthe filler serving to give the product the desired hardness.

The parafi'ine serves as a lubricant, primarily to wet the batch, whilethe polyethylene functions as a lubricant which helps release the curedproduct from the mold. The anti-oxidant limits oxidation of the endproduct.

The ultra-marine blue is a coloring agent which cooperates with .thetitanium dioxide, a white coloring material, and the black color masterbatch, to produce a desired gray color for the final product.

The elastomer master batch is separately mixed becauseof the affinity ofits two ingredients for each other; and the ingredients of the blackcolor master batch are also separately mixed in a batch as a preferredmeans of preparing the coloring black so as to standardize the coloringof the product.

The preferred milling procedure for combining the ingredients set forthabove in Table I is as follows: First, the elastomer master batch andthe black color master batch are prepared. These master batches, andalso the final batch containing all of the materials, are preferablymixed on water cooled rolls. In preparing the elastomer master batch theprocedure is preferably as follows: band the Neoprene GN on the millrolls and mill in the Butaprene SL; and bring the mill roll temperatureup to F. minimum for fluxing of the Butaprene into the Neoprene.

The overall material batch is preferably prepared according to thefollowing steps:

(1) Place the. elastomer master batch and the black color master batchon tight mill rolls and blend together well by cutting back and forth.

(2) Add in Neoprene WRT and adjust mill roll opening for proper bank;blend wellby cutting back and forth.

(3) Add the stearic acid and blend in.

(4) Add the magnesium oxide.

(5) Blend in the polyethylene.

(6) Blend in the anti-oxidant.

(7) Mill in the titanium dioxide and ultra-marine blue together.

contact-positioning web 23 so as to apply a coating of bonding materialthereto.

Although the present invention is not limited to the use of anyparticular bonding agent or to any particular method of applying thebonding agent to the contact positioning web, the following is anexample of a bonding agent and of the method of applying it which haveproved useful in practice: First, the contact-positioning web 23 iswashed in a suitable solvent, such as toluene, which both cleans andetches the surfaces of the web 28. Second, the web 28 is coated, as byspraying, with a primer coating which adheres well to the material ofthe Web 28. A suitable primer has been found to be Chemlock No. 203which is oven-dried after application for about 10 minutes at about 200F. to dry off its solvents. Next, a final coating is applied, as byspraying, of a material which adheres well both to the primer coatingand to the elastomer material of the insulation body 10. A suitablefinal coating is Chemlock No. 220, which again is dried for about 10minutes at 200 F. to drive 01f its solvents. These coatings areessentially rubber-based cements. In practice, this coating of bondingagent is on the order of about two thousandths of an inch thick, and theopenings in the stop rings 22 are provided slightly larger than thedesired final opening sizes in order to compensate for the thickness ofthe coating of bonding agent. The contact-positioning web 28 may, forconvenience, be left connected to its support 32 during the applicationof the coating of bonding agent, and then after the bonding agent hasbeen applied and dried, the positioning web 28 may be broken away fromthe support 32 so that it can be placed in the mold as hereinafterdescribed.

Referring now particularly to FIGS. 1, and 6, the mold structure thereshown is by way of illustration only, and it will be understood thatdifferent mold structures may be employed for accomplishing the sameresults, with contemplated production molds including moldable cavitiesand automatic actuating means.

The mold structure is disposed on a suitable table or base 36, the lowerportion of the mold structure including a back-up plate 38 disposed onthe table or base 36, with an insert holder plate 40 on top of back-upplate 38. The insert holder plate 40 supports a pin mounting insert 42within which a multiplicity of core pin members 44 are mounted so as toproject upwardly therefrom. Each of the core pin members 44 has a flatinner end surface 46 disposed at right angles to the axis of the corepin member, with a registry projection 48 extending axially from theflat end surface 46. Further, each core pin member 4 has a cylindricalend portion 50 terminating at the fiat inner end surface 46, with a stopcollar 52 just below this cylindrical end portion 50. The distance fromstop collar 52 to the flat inner end surface 46 is substantially equalto the axial extent of each of the stop rings 22 forming a part of thecontact positioning web 28.

Disposed above the insert holder plate 40 is a mold cavity plate 54having a mold cavity 56 therein. The core pin members 44 extend onlypart way through the mold cavity 56.

Above mold cavity plate 54 is another insert holder plate 58 withinwhich a pin mounting insert 60 is supported, the insert 60 serving tosupport a multiplicity of core pin members 62 which are axially alignedwith respective core pin members 44. Each of the core pin members 62 hasa flat inner end surface 64, with a registry recess 66 therein. In theassembled condition of the mold members as shown in FIG. 1 and FIG. 6,the flat inner end surfaces 46 and 64 of opposed pairs of the respectivecore pin members 44 and 62 will abut against each other, with theregistry projections 48 entering respective registry recesses 66 foralignment of the core pin members. Thus, the core pins employed in themold structure may be termed split core pins, in

that each of them is divided into two sections which come into the moldcavity from opposite directions.

When the mold is open, with insert holder plate 58 and the structureabove it removed from mold cavity plate 5d, and after a precedinginsulation body has been removed from the mold cavity, the contactpositioning web 28 is set in the mold cavity 56 with each of the stoprings 22 slidably engaged over the cylindrical end portion 50 or" arespective core pin member 4-4, in the manner shown in FIG. 5. In thecontact positioning web 28 the center-to-center distances between the respective stop rings 22 are the same as the center-tocenter distancesbetween the respective core pin members 44, so that the contactpositioning web 28 may be easily slipped into its operative position inthe mold cavity as shown in FIG. 5. When the contact positioning web 23is thus positioned in the mold cavity, the upper insert holder plate 53is moved down flat against the mold cavity plate 54 as shown in FIGS. 1and 6, and in this position of the mold parts the stop rings 22 will beaccurately positioned in the mold cavity between the respective core pinstop collars 52 and the respective flat inner end surfaces 64.

The mold structure is completed by a back-up plate 68 above the insertholder plate 58, back-up plate 68 having a cylindrical recess 70 thereinwithin which the elastomer material is placed for injection into themold cavity. A sprue '72 extends down from the cylindrical recess 70,communicating with a runner or transfer passage 74 in mold cavity plate54, which in turn communicates with a feeder port '76 through which theclastomer material enters into the mold cavity 56. A piston member '78is slidable in the cylindrical recess 70, and is connected to a plungerof a hydraulic press, so that downward movement of plunger 80 will forcepiston member '78 downwardly in the cylindrical recess 70 to force theelastomer material into the mold cavity.

The various parts of the mold may be aligned by any suitable means, asfor example by a plurality of aligning dowels 82 which are disposed inrespective openings d4 through the various parts of the mold structure.

When the elastomer material is thus injected into the mold cavity, itwill flow about the rings 22 and connecting links 30 of the positioningweb 28, so that the stop rings 22 will be secure.y bonded to theelastomer material.

The pressure for injecting the elastomer material into the mold is onthe order of between about 2000 p.s.i. and about 4000 p.s.i.

Removal of the insulation body 10 from the mold is effected byseparation of the required mold parts, the core pin members 44 beingwithdrawn from the rear end of the insulation body, and the core pinmembers 62 being withdrawn from the forward end of the insulation body.The resiliency of the insulation body 10 will permit flexing of theinsulation material in the re gion of the terminal-receiving bores 16 topermit this withdrawal of the core pin members, and by placing the stopring members 22 at the juncture between the opposed core pin members 44and 62, the substantially rigid rings 22 will not interfere with thiswithdrawal of the core pin members.

One of the characteristics of most elastomer materials is that theyundergo a substantial amount of shrinkage when they cool. A typicalexample of this shrinkage is approximately 18 thousandths of an inch ofshrinkage per inch of the part during cooling from the range of about300 to 320 F. down to room temperature. By providing the thin,relatively weak connecting links or bridging members 30 between the stoprings 22 in the contact-positioning web 28, the stop rings 22 arepermitted to shift slightly toward each other during the shrinkage ofthe elastomer material, so that the stop rings 22 in the final cooledpart will be correctly aligned in their respective terminal-receivingbores 16. Thus, dur- (8) Blend in the silicious material (HiSil 233),clay, and parafiine (cut into small pieces).

(9) Blend the Zinc oxide in well.

Next, the curing agent is milled in well. However, if the batch hasbecome too hot before adding the curing agent, cut the batch off of therolls and allow to cool before adding the curing agent and milling it inon the rolls. After the curing agent is milled in well, cut the batchoff of the rolls, tighten the rolls, and then roll up the batch and passit through the rolls endwise, doing this preferably from 6 to 8 times.Then, open the rolls and sheet the material off approximately A1 inchthick.

The curing temperature of the mold is preferably between about 300 F.and 320 F. The molding time from injection .of the material untilremoval of the completed insulator body from the mold is preferably fromabout 9 to about 12 minutes.

The completed elastomer insulator produced according to the aboveformula has the following physical properties:

Table II Shore A hardness 81 Tensile strength (p.s.i.) 2320 Elongationpercentage 5 65 Tear strength (Die B) 275 Mooney Scorch to 10 point riseat 250 F.,

minutes 9 /2 Plasticity 72 Although only a single formula has been setforth herein in detail for the preparation of the elastomer materialcomprising insulation body 10, it will be apparent that those skilled inthe art can, from the above example, readily produce the presentinsulators of various elastomer materials and with various hardnesses asmay be required for different types of electrical connectors.

The insulation body 16 which is molded in the apparatus of FIGS. 1, 5and 6 has a forward face 12 and a rearward face 14, with a multiplicityof parallel terminalreceiving bores 16 extending axially through bodyit) from the rearward face 14 to the forward face 12. Each of theterminal-receiving bores 16 has at least one forwardly facing annularshoulder therein which is engageable by a rearwardly facing shoulder ona respective contact terminal when the contact terminal is inserted intothe bore to position the terminal against rearward moveanent in theinsulation body. In the particular insulation body 10 which is shown inthe drawings, there is the forwardly facing shoulder 18 in the borewhich serves this function. Although only one such forwardly facingshoulder is required in the bore for positioning the terminal againstrearward movement, in the particular bore configuration shown in thedrawings there is a second forwardly facing shoulder 26 in the borewhich also assists in holding the contact terminal against rearwardmovement;

A multiplicity of substantially rigid stop rings 22 are molded into theinsulation body it) so as to be generally circumferentially positionedwithin the respective terminal-receiving bores 16. Each of thesesubstantially rigid stop rings 22 has an exposed, rearwardly facingannular shoulder 24- in its respective bore 16 which is engageable by aforwardly facing shoulder on the terminal member so as to limit forwardpositioning of the terminal member in the bore. The applicants newmethod and structure for securing these rigid stop rings 22 in theiroperative positions in the respective terminal-receiv ing bores 16comprise important parts of the present invention.

The stop rings 22 in the respective bores provide substantially rigidstop means against which the contact terminals will seat when they arepushed into their operative positions in the insulation body. The stoprings 22 thus provide reliable positioners for the contact terminals.The hardness of the rigid stop rings 22 causes an audible click noise tobe heard when each contact terminal reaches its final position asdefined by the respective rigid stop ring 22, release of flexed orcompressed resilient material of the insulation body when the contactterminal arrives at this final position helping to drive the contactagainst the shoulder of the stop ring 22. In addition to this positiveaxial positioning of'the contact terminals by the rigid stop rings 22,the stop rings also assist in final contact stabltiy by limiting lateralshifting of the contact terminals in their respective bores.

Although therigid stop rings 22 will normallyrbe employed to arrestforward axialmovement of contact terminals which have ben inserted intothe insulation body bores from the rear, it will be apparent that the.rigid stop rings 22 can also be employed to limit rearward movement ofcontact terminals of the forward entry type which are inserted from theforward ends of the bores.

The inside diameters of the rings 22 as theya're finally molded intoposition in the insulation body 10 are slightly larger thancomplementary cylindrical wall portions of the respective contactterminals, and the ends of the passages which extend through the stoprings 22 are preferably radiused or chamfered so as to facilitate entryof the contact terminals therethrough.

Each of the terminal-receiving bores 16 of insulation body It) ispreferably provided with a constriction 26 in the rear portion of theinsulation body which resiliently engages either the conductor from thecontact or a rear portion of the contact itself for sealing purposes.

An important part of the present invention is the provision of a unitarycontact-positioning web 28 comprising all of the substantially rigidstop rings 22 for the insulation body 10 and a plurality of connectinglinks or bridging members 39 between the stop rings 22 which fix thepositions of the stop rings with respect to each other for insertion andpositioning of the stop rings 22 in the mold. The connecting links orbridging members 3d are made considerably thinner and weaker than thebodies of the stop rings 22, and a minimum number of these connectinglinks 30 is provided, so that the connecting links can break or shrinkor bend when the molded insulation body shrinks as it cools after it isremoved from the mold. The contactpositioning web 28 which isillustrated in FIGS. 2 and 3 and which is employed in the mold structureshown in FIGS. 1, 5 and 6 includes only four of the stop rings 22, so asto simplify the drawings as they relate to the molding process. However,in many instances there will be a much larger number of the stop rings22 formed in the contactpoitioning web 2% 'For example, inthe'contact-positioning web 34 which is shown in plan view in FIG. 4, 550f the stop rings 22 are provided.

The contact-positioning web 28 is preferably composed of a substantiallyrigid insulating material which has high dielectric characteristics. Itis preferred to employ a material which has dielectric characteristicsthat are as good as, or better than, those of the elastomer material inthe insulation body iii. Presently preferred materials for the contactpositioning web 28, to which the present invention is not necessarilylimited, are nylon, Lexan and Delrin (Lexan and Delrin being well-knownproprietary compositions), these materials having a hardness within theregion of from about. 107 to about Rockwell R. These presently preferredmaterials are thermoplastic materials, and with such material the web 28can be produced by injection molding if desired. Thermosettingmaterialscould also be employed for the web 28.

Where the web 28 is made by injection molding, it is sometimes useful toretain some of the extra molded material which was in the feed channelsof the mold as a support 32 for handling the web 28 during preparationof the web 23 for the process of molding insulation body 10.

It is important that the substantially rigid stop rings 22 be bonded tothe elastomer material of insulation body 10 during the process ofmolding the insulation body 10, and in order to effect such a bond, itis preferable to treat the ing shrinkage of the insulation body 10 as itcools, the thin connecting links 30 will bend or warp or break asrequired, and will not obstruct the required movement of the stop rings22 with the shrinking insulation body. Accordingly, it is by means ofthe relatively thin and weak connecting links 30 that the contactpositioning web 28 is permitted to be slipped freely over the ends ofthe core pin members 44 in the mold, accurately registering with thesecore pin members, while the substantially rigid stop rings 22 areproperly aligned in their respective terminal-receiving bores 16 whenthe final part has cooled to room temperature.

The core pin members are preferably provided with hard surface finishes,as for example chrome plated finishes, so that the bonding agentemployed on the stop rings 22 will not adhere to the core pins and thuscause damage when the core pin members are extracted after theinsulation body 10 has been molded.

It is to be noted that the contact positioning web 28 provides anaccurate check for the positioning of the core pins when it is placed inits operative position as shown in FIG. 5. If any of the core pinmembers 44 are bent out of alignment, the web 28 will not fit as itshould.

If the contact-positioning web 28 were composed of a thermosettingplastic material, the coating of bonding material could probably beeliminated. The thermosetting web 28 in this case would only bepartially cured when formed, and would be in this partially curedcondition when placed in position as shown in FIG. ready for the moldingof the insulation body 10. Then, during the curing of the insulationbody 19, curing agents in the elastomer material would assist incompleting the cure of the thermosetting material of the contactpositioning web 28.

In FIG. 8 a pin contact terminal is shown operatively positioned in oneof the contact terminal-receiving bores 16 of insulation body 10. Thispin contact terminal 86 has a contacting portion 88 which projectsforwardly from the forward face 12 of the insulation body, and has aforward enlarged portion 91} which presents a rearwardly facing shoulderthat is engageable against the forwardly facing shoulder 18 in the bore16 to secure the terminal 86 against rearward axial movement in thebore. The pin contact terminal 86 also includes an annular collar 92which presents a forwardly facing shoulder that strikes the rearwardlyfacing shoulder 24 of stop ring 22 so as to limit forward positioning ofthe contact terminal 86 when terminal 86 is inserted into the bore 16from the rear of the insulation body. Collar 92 also presents arearwardly facing shoulder which will engage against the forwardlyfacing shoulder 20 to assist in preventing rearward axial movement ofthe terminal. The terminal 86 also includes a rear cup or sleeve portion94 within which the exposed conductor of a wire 96 is secured, as bycrimping, soldering, welding or the like, to effect electrical andmechanical connection.

FIG. 9 illustrates an insulation body a having bores 16a therethroughwhich receive respective socket contact terminals 86a, the socketcontact terminals 86a being inserted into the bores 16a from therearward face 14a of the insulation body 16a.

Bores 16a are the same in configuration as bores 16 of insulation body10, except for an elongated forward cavity portion 98 of each bore tothe rear of the forward face 120:. Each socket contact terminal 86a hasa tubular forward contact portion 88a within which an opposed forwardcontacting portion 88 of a pin contact terminal 86 will mate. Theinsulation body 10a is molded in the same manner as insulation body 10,and contact positioning web 28 with its substantially rigid stop rings22 is molded into insulation body 10a in a similar position as ininsulation body 10 so as to cooperate with the socket contact terminal86a in the same manner as with the pin contact terminal 86.

FIGS. 10 and 11 illustrate a modified insulation body ltib having aplurality of bores 16b therethrough which are adapted to receive pincontact terminals 86. The insulation body 10b is molded in the samemanner as insulation body 10, with a contact positioning web 28]) moldedtherein. However, the substantially rigid stop rings 22b differ fromstop rings 22 in that each of the stop rings 22b has integrally formedtherewith a plurality of forwardly, generally axially extending springfingers 100. The spring fingers 100 as illustrated in FIGS. 10 and 11are three in number, and each includes a section 102 which inclinesforwardly and radially inwardly, an offset portion 1% extending radiallyoutwardly from the forward end of each of the inclined sections 102, anda straight axial section 106 at its forward end. The offset portion 104presents a forwardly facing shoulder 108.

The operation of the structure shown in FIGS. 10 and 11 is as follows:When a pin contact terminal 86 is inserted into bore 16b from the rear,the forward enlarged portion 90 will engage against the inclinedsections 102 of the fingers 160, camming the fingers radially outwardlyso that the enlarged contact portion 90 can pass between the fingers toa point just forward of the forwardly facing finger shoulders 108, whichis the position :of the enlarged contact portion 919 when the collar d2of the contact strikes the rearwardly facing shoulder 24 of thesubstantially rigid stop ring 22b. This outward camming of the springfingers is permitted by virtue of the fact that the spring fingers arebacked up by the resilient elastomer insulation body material, and whenthe enlarged contact portion W passes forwardly in front of the fingershoulders 1198, the fingers will snap back radially inwardly so that theshoulder 1133 will then be behind the enlarged contact portion 99 toprovide a positive stop means against withdrawal of the contact 86.

ItWill be noted from FIG. 10 that the forwardly facing shoulders 108 ofthe spring fingers 101) are generally disposed in a radial plane, andwith this construction the fingers 1% will normally have to be flexedradially outwardly by a suitable tool inserted into bore 16b from theforward end of the insulation body in order to remove the contactterminal rearwardly out of the bore.

The structure shown in FIG. 12 is similar to that of FIGS. 10 and 11,with similar parts designated by refer ence character 0 instead of b.However, the shoulders 1030 on the spring fingers 11900 in FIG. 12differ from the corresponding shoulders 108 in FIG. 10 by being inclinedforwardly and radially outwardly so that upon the application of apredetermined amount of rearward force to the contact terminal, theterminal will cam the fingers 1490c radially outwardly for removal ofthe terminal from the bore without requiring the use of a front entrytool.

While the instant invention has been shown and described herein in whatare conceived to be the most practical and preferred embodiments, it isrecognized that departures may be made therefrom within the scope of theinvention, which is therefore not to be limited to the details disclosedherein, but is to be accorded the full scope of the claims.

I claim:

1. An electrical connector insulator which comprises a body of resilientinsulation material having a plurality of parallel contactterminal-receiving bores extending entirely therethrough, and acontact-positioning web cornposed of insulation material bonded withinsaid body said contact-positioning web comprising a plurality of annularsubstantially rigid stop members and a plurality of bridging members,said stop members presenting stop shoulders in the respective boresintermediate the ends of the bores which are engageable against opposedshoulders on respective contact terminals inserted in said bores tolimit axial movement of the contact terminals in one direction in thebores.

2 An electrical connector insulator as defined in claim 1, wherein saidbridging members are substantially weaker than said stop members.

3. An electrical connector insulator as defined in claim 1, wherein saidstop members and bridging members are substantially coplanar in a planedisposed at rig-ht angles to the axes of said bores.

4. An electrical connector insulator which comprises a body ofinsulation material having a forward face and a rearward face and havinga plurality of parallel contact terminal-receiving bores extendingtherethrough from said rearward face to said forward face, and a contactpositioning web composed of insulation material bonded within said body,said contact positioning web including a plurality of substantiallyrigid stop rings and a plurality of bridging members connecting saidrings, said stop rings presenting rearwardly facing annular shoulders inthe respective bores intermediate the ends of the bores which areengageable against forwardly facing opposed shoulders on a plurality ofcontact terminals to limit forward positioning of the contact terminalsupon insertion of the terminals into the respective bores from the rearof the,

insulation body, each of said stop rings having a plurality of integralspring fingers extending forwardly and radially inwardly therefrom, eachspring finger having a shoulder thereon which faces forwardly in thebore, said spring fingers being cammed radially outwardly by aprojection on each contact terminal and then springing radially inwardlybehind the projection on the terminal to limit rearward movement of theterminal when the terminal is moved forwardly into its forwardmostposition.

.5. An electrical connector insulator which comprises a body ofresilient insulation material having a forward face and a rearward faceand having a plurality of parallel contact terminal-receiving boresextending there through from said rearward face to said forward face,and a contact-positioning web composed of insulation material bondedWithin said body intermediate the faces of said body and disposed in ageneral plane transverse of the axes of the bore, said web including aplurality of stop rings having substantially greater rigidity than thematerial of the body and a plurality of bridging members connecting saidrings, said rings being disposed in circumscribing relationship with therespective bores and presenting annular shoulders in the respectivebores intermediate the ends of the bores which are engageable againstopposed shoulders on a plurality of contact terminals to block movementand limit the positioning of the contact terminals upon insertion of thecontact terminals into the respective bores of the insulation body.

6. An electrical connector insulator as definedin claim 5 wherein thestop rings are closely spaced in a symmetrical pattern.

7. In an electrical connector which comprises a body of resilientinsulation material having a forward face and a rearward face and havinga plurality of parallel contact terminal-receiving bores extendingtherethrough from said rearward face to said for-ward face, a unitarycontactpositioning web bonded within said body'intermediate the faces ofsaid body during the formation of the body and disposed in a generalplane transverse of the axes of the bore, said web being entirelycomposed of insulation material of substantially greater rigidity thanthe material of the body and comprising a plurality of stop ringsclosely spaced in a pattern corresponding to the transverse pattern ofthe bores, said rings being in circumscribing relationship with therespective bores and presenting annular shoulders in the respectivebores intermediate the ends of the bores which are engageable againstopposed shoulders on a plurality of contact terminals to block movementand limit the positioning of the contact terminals upon insertion of thelatter into the respective bores, said web including bridging elementsinitially interconnecting said stop rings and retaining the same in saidpattern during formation of the body, and said bridging elements beingdeformable or shearable under stresses tending to change relativetransverse positioning of stop rings during formation of the body.

References Cited by theExaminer UNITED STATES PATENTS 1 2,465,656 3/49Morin.

2,559,651 7/51 McLarn 392- 17 X 2,753,534 7/56 Sprigg' 339-49 2,876,4993/59 Schultz.

3,028,574 4/62 Di Monte 339-51 FOREIGN PATENTS 231,278 11/60 Australia.

604,762 10/34 Germany.

JOSEPH D. SEERS, Primary Examiner.

ALFRED S. TRASK, Examiner.

1. AN ELECTRICAL CONNECTOR INSULATOR WHICH COMPRISES A BODY OF RESILIENTINSULATION MATERIAL HAVING A PLURALITY OF PARALLEL CONTACTTERMINAL-RECEIVING BORES EXTENDING ENTIRELY THERETHROUGH, AND ACONTACT-POSITIONING WEB COMPOSED OF INSULATION MATERIAL BONDED WITHINSAID BODY SAID CONTACT-POSITIONING WEB COMPRISING A PLURALITY OF ANNULARSUBSTANTIALLY RIGID STOP MEMBERS AND A PLURALITY OF BRIDGING MEMBERS,SAID STOP MEMBERS PRESENTING STOP